White opaline glass lampshade

This white opaline tulip is absolutely charming with its delicate bell-shaped form reminiscent of lily of the valley, its curved and wavy edges. It can be placed on a bulb socket and then secured with the screw washer on the socket, or perhaps on a clip system It's difficult to date it, but I would lean towards the first half of the 20th century; I find it has a very "Art Nouveau" style. It is in very good condition, with neither cracks nor chips, not even a scratch, just a very slight small mark at the fixing opening. It measures 11 cm in height, 14.5 cm in maximum width (at the level of the waves), approximately 8.5 cm in diameter at the narrowed corolla, and the upper opening (where the socket will be inserted) has a diameter of 2.8 cm.